The present invention relates to plunge routers, and in particular, to methods and apparatus for adjusting the bit of the router relative to the base plate of the router when mounted underneath a table. The adjustment apparatus can be retrofitted to a wide variety of existing plunge routers, or provided as a feature of newly manufactured plunge routers.
With a typical plunge router a base plate is used to support the router against a surface of the material to be routed. A router bit is typically centered the in base and rotated by a motor. Handles are provided to grip the router if it is used in a hand-held mode. Plunge routers employ support members or columns in between the base and the main router housing. The support columns are longitudinally slideable in receiving chambers. Springs push against the interior ends of the support columns to urge them outwardly, biasing the base away from the housing of the router. This allows the base to be positioned in a rest position such that the bit does not extend past the plane of base. The base of the plunge router can therefore be placed on a surface to be routed without damaging the surface. Once in position, force can be applied to the router housing (against the springs) to move the bit down to the work surface to begin routing, for example in the middle of a work surface. Without such an arrangement, it would be very difficult to position a router to a particular starting point on a surface to be routed.
Typically, plunge routers allow some adjustment of the position of the base relative to the bit. Normal bit adjustment is provided by a knob at the end of a threaded rod, which extends along the motor housing of the plunge router. The knob can be turned to move the base farther away or closer to the bit as desired.
It is sometimes desirable to invert a plunge router and install it upside down in a table or other support so that it may be used as a table router. Therefore, most plunge routers have the flexibility of being used in a portable, hand-held manner or in a table-mounted configuration. While the normal adjustment mechanism provided on typical plunge routers is fairly satisfactory when the plunge router is used in the hand-held mode, it is difficult to use when the plunge router is fixed underneath a table. The operator typically has to reach underneath the table blindly or bend down in order locate the knob to adjust the router.
Therefore, it would be desirable to provide a mechanism for adjusting the router when mounted underneath a router table, which can be easily disconnected or disassembled from the original unit to enable use in a hand-held operation.
It would therefore be advantageous to provide methods and apparatus for simple adjustment of a table mounted plunge router. It would be advantageous to provide such an adjustment mechanism that does not require extensive modifications to the original unit and which would not limit its original functionality. It would be further advantageous to provide an adjustment mechanism which can be easily disassembled or disconnected from the router to enable hand-held operation of the router. It would be further advantageous to enable easily readable router adjustments in a comfortable manner with minimal effort. It would be advantageous to provide an adjustment mechanism which is essentially universal in nature and that can be retrofitted or installed as original equipment on a variety of types of plunge routers.
The methods and apparatus of the present invention provide the foregoing and other advantages.